Re: Dual & Quad Core processors

"Rob Mueller" <robm@xxxxxxxxxxx> · Sat, 1 Mar 2008 13:34:41 +1100

  Does Cyrus-imapd take advantage of Dual and\or Quad core processors? We 
  are looking at upgrading our server to either 2x Dual core Xeon?s or 1 x Quad 
  core Xeon processor. Does Cyrus have the ability to take advantage of 
  this?
Since it uses a multi-process model, 
yes it does.

However that's not what you should 
upgrade your servers for. cyrus uses very little CPU time on any modern 
processor. Even with 10,000's of users, our servers with 3 year old 2.4Ghz 
Netburst Xeons never get more than about 30% CPU usage (out of 400% because 
they're dual processor, hyper-threaded machines).

Instead cyrus is incredibly IO 
hungry. You should have as much RAM as possible for caching, and a battery 
backed NVRAM RAID controller to try and improve the random write IO that's 
generated. These will do much more for you than upgrading your CPU 
will.

Rob

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